Spotlight on Pumps and Valves

Solenoid pinch valvesThe Intelivalve line of solenoid pinch valves from Acro Associates Inc. is designed to accommodate the types of tubing used most frequently in fluid-based medical devices with single-use or disposable fluid paths. Thus, it can accommodate 1⁄8- to 7⁄16-in. OD flexible tubing, tubing with durometers up to 75 Shore A, and tubing materials with media pressure ratings up to 30 psi. The valves have a dedicated sensor and controller; thus, not only are power management and state sensing built-in features, but the valves emit almost imperceptible noise and offer an option for tube detection, cycle monitoring, and fault logging. To facilitate integration, multiple controllers can be linked and enabled to communicate via a controller area network or the RS-422 or RS-485 interface. These pinch valves are suited for use in dialysis treatment equipment, blood-collection devices, perfusion systems, and drug-administration systems. They can also serve as emergency shutoff valves, direct administration devices, or valves for precise dosing, filling, or mixing.Acro Associates Inc.Concord, CA

Microfluidic valvesCombining the proven rocker principle with an innovative actuator enables Twin Power microfluidic valves from Burkert Fluid Control Systems to maintain given levels of performance and reliability in a smaller valve design with lower power consumption. The dual-solenoid valves are available in 10-, 16-, and 22-mm sizes. They also exhibit the flow and pressure resistance typically found in larger valves, making them suitable for applications in which space is critical or strong performance is needed. The 10-mm valve comes with orifices sized up to 1.6 mm and with pressure resistance as high as 73 psi; the 16-and 22-mm models are available with a 3.0-mm orifice. Maximum pressure resistance is 29 psi for the 16-mm valve and 73 psi for the 22-mm valve.Burkert Fluid Control SystemsIrvine, CA

Microminiature vacuum pumpsHigh-performance, maintenance-free Type NPK04microminiature swing-piston pumps for transferring, evacuating, or compressing air in medical and analytical instrumentation generate high flows at vacuum or pressure. Available from KNFNeuberger Inc., the 2.5-in.-long pumps deliver free-flow rates to 4 L/min and can be optimized to produce elevated levels of vacuum or pressure: up to 21 in.Hg or 45 psig, respectively. Also, standard pumps can be customized to meet particular OEM requirements. The swing piston incorporated in the design enables the pump to move media oil-free. Users can specify standard dc motors or brushless dc motors. Supplied ready to install and able to operate in any position, these pumps run quietly with minimal vibration and provide sustained energy-efficient service.KNFNeuberger Inc.Trenton, NJ

Solenoid pumpDesigned to offer medical device engineers design flexibility, the LPL2 inert solenoid pump from The Lee Co. has a distinctively engineered port head that accommodates tubing connections and manifold mounting. This design enables the medical device developer to test the fluidic system using connections to soft 1⁄16-in. tubing. Once the system design has been finalized, the same pump can then be manifold-mounted by means of standard O-rings. The pump additionally features a contoured end cap that is compatible with standard AMP connectors, providing secondary connector retention.The Lee Co.Westbrook, CT

Piezoelectric diaphragm micropumpsBased on piezoelectric diaphragm pump technology, the self-priming micropumps in the MP-6 series from Servoflo Corp. deliver air, gases, or liquids in low-flow portable medical equipment applications, such as drug-delivery devices, infusion pumps, nebulizers, respiratory equipment, and point-of-care platforms. These stock pumps measure 30 × 15 × 3.8 mm, consume less than 200 mW of power, and are capable of cycling several-hundred times per second. Typical flow values are 18 ml/min maximum with 100-mbar backpressure for gas and 7 ml/min with 600-mbar backpressure for water. Custom pump modifications can be made to meet customer requirements. A polypropylene version is available for handling corrosive media. Evaluation kits are available.Servoflo Corp.Lexington, MA

Brushless dc air pumpThe 230-series brushless dc WOB-L air compressor is designed for medical device applications calling for a lightweight, compact pump with variable output. The 3.8 × 2.64 × 3.63-in., 1.2-lb pump from Thomas Div. generates output between 1000 and 3000 rpm and features an efficient brushless dc motor, an enclosed crankcase to keep noise to 40 dBa, and proprietary piston technology. Maximum flow is 0.50 cu ft/min, and maximum pressure is 30 psig. The pump runs on 12 V, draws 3.3 A of current, and has a motor rating of 40 W. It operates at temperatures between 50° and 104°F.Thomas Div.Sheboygan, WI

OEM pumps for surgical ablationThe 400RXMD range of OEM pumps, based on the manufacturer’s RX pump technology, is designed for such surgical ablation applications as treatment of cardiac arrhythmia and cancer. Watson-Marlow Pumps Group has incorporated numerous customer-requested improvements into this pump series. Among them are a choice of pressure settings to accommodate specific application requirements, a mechanism that enhances flow accuracy, and a tube holder designed to ensure that a newly loaded tube goes into the right position whenever the safety lid is closed. Pressure, flow, and rotational direction can be set to suit the user’s needs. Used in equipment employing radio-frequency ablation, the pump circulates cooling fluid to provide precise temperature control so that the treatment will be more effective and prevent scarring. It is available in 10 variants offering flow rates to 500 ml/min at 550 rpm and pressure settings ranging up to 8 bar.Watson-Marlow Pumps GroupWilmington, MA